TWI744482B - Wafer undulation detection method and grinding device - Google Patents

Abstract

In the case of grinding a wafer using a grinding device, it is designed so that it is not necessary to take out the wafer from the grinding device and measure the fluctuation with another measuring device to prevent an increase in the number of processes required for processing. A method for detecting the undulation of a wafer includes a holding step of holding the wafer (W) on the holding table (400), and contacting the flat transparent plate (50) with the wafer (W) held on the holding table (400) The contact step and the irradiation step of irradiating light from the side of the transparent plate (50) detect the fluctuation of the wafer (W) by the interference pattern (R) generated in the irradiation step.

Description

Wafer undulation detection method and grinding device

The present invention relates to a detection method for detecting the undulation of the ground surface of a wafer before grinding or the undulation of the ground surface of a wafer after grinding, and a grinding device capable of grinding the wafer and detecting the undulation .

A plate-shaped workpiece such as a silicon wafer is ground by a grinding device (for example, refer to Patent Document 1) to be thinned to a predetermined thickness, and then divided by a cutting device or the like to become individual element wafers. It is used in various electronic devices. [Prior Technical Documents] [Patent Documents]

[Patent Document 1] JP 2009-094247 A

[The problem to be solved by the invention]

When the processing conditions in the grinding are not appropriate or the components of the grinding device or the grinding wheel have some abnormalities, the thickness of the ground surface of the wafer after grinding may be inconsistent. The ups and downs caused (the deformation caused by the height difference of the surface). In addition, in order to detect the ups and downs of the ground surface of the wafer after grinding or the ground surface of the wafer before grinding, conventionally, the wafer is temporarily taken out from the grinding device and transported to another measuring device. This measurement device performs the measurement of wafer undulations. Therefore, there is a problem that the number of processes required for processing increases.

Therefore, when using a grinding device to grind a wafer, how to measure the fluctuations with another measuring device without removing the wafer from the grinding device to prevent an increase in the number of processes required for processing is a question to be solved. . [Technical means to solve the problem]

The present invention to solve the above-mentioned unsolved problem is a method for detecting the fluctuation of a wafer, which includes a holding step of holding the wafer on a holding table and contacting a flat transparent plate with the wafer held on the holding table. The contact step and the irradiation step of irradiating light from the side of the transparent plate detect the undulation of the wafer by the interference pattern generated in the irradiation step.

In addition, the present invention for solving the above-mentioned problems to be solved is a grinding device, which is equipped with a grinding means and a chuck platform for holding a wafer, and is characterized by further comprising: a flat transparent plate; And the means for holding the transparent plate; and the means for moving the holding means closer to or away from the wafer; and the means for irradiating light from the side of the transparent plate; and the means for photographing interference patterns generated by light irradiation. [Effects of Invention]

The method for detecting the fluctuation of a wafer of the present invention includes a holding step of holding the wafer on a holding table, a contact step of bringing a flat transparent plate into contact with the wafer held on the holding table, and a step of irradiating light from the side of the transparent plate. In the irradiation step, the fluctuation of the wafer can be detected by the interference pattern generated in the irradiation step. In addition, the method for detecting the fluctuation of the wafer of the present invention can be implemented in the grinding device without requiring the structure of the grinding device to be complicated. Therefore, it is not necessary to remove the wafer from the grinding device in order to detect the fluctuation of the wafer. It is taken out and transported to another measuring device, so it is possible to prevent an increase in the number of processes required for processing.

The grinding device of the present invention includes a flat transparent plate, a holding means for holding the transparent plate, a moving means for moving the holding means close to or away from the wafer, an irradiating means for irradiating light from the side of the transparent plate, and a light-emitting device. The imaging method of the interference pattern generated by the irradiation can detect the fluctuation of the wafer in the grinding device. Therefore, it is not necessary to take out the wafer from the grinding device and transport it to another measuring device in order to detect the undulation of the wafer, and it is possible to prevent an increase in the number of processes required for processing. In addition, it is possible to detect the fluctuation of the wafer in the grinding device, thereby quickly detecting the factors that cause fluctuations that exceed the allowable value on the ground surface of the wafer, that is, the various components of the grinding device (such as The rotation axis of the grinding wheel, etc.), the abnormality of the grinding wheel, and the abnormality of the processing conditions.

The grinding device 3 shown in FIG. 1 is a device that performs grinding processing on the wafer W attracted and held by the chuck table 30. The wafer W shown in Fig. 1 which is thinned by grinding processing is, for example, a round semiconductor wafer made of silicon. A large number of elements are formed in the grid-shaped area partitioned. The surface Wa is protected by, for example, a protective tape (not shown). The back surface Wb of the wafer W becomes the ground surface to be ground.

The front (-Y direction side) on the base 3A of the grinding device 3 is an area where the wafer W is loaded and unloaded on the chuck table 30 by the robot arm 330 capable of transporting the wafer W. The rear side (+Y direction side) on the susceptor 3A is processed by the rough grinding means 31 for rough grinding the wafer W or the finish grinding means 32 for finish grinding the wafer W The grinding area of the wafer W held on the chuck platform 30.

On the front side of the base 3A, a first cassette 331 for storing the wafer W before grinding and a second cassette 332 for storing the wafer W after grinding are arranged. In the vicinity of the first cassette 331 and the second cassette 332, a robot arm with the function of unloading the wafer W before grinding from the first cassette 331 and carrying the ground wafer W into the second cassette 332 is arranged 330.

The robot arm 330 is configured such that a holding portion 330b for holding the wafer W is provided at the tip of the bendable arm portion 330a, and the movable area of the holding portion 330b is arranged to align the wafer W before processing to a predetermined position The alignment means 333 and the cleaning means 40 for cleaning the polished wafer W.

The first conveying means 335 is arranged adjacent to the positioning means 333, and the second conveying means 336 is arranged adjacent to the cleaning means 40. The first conveying means 335 has the function of conveying the wafer W before grinding placed on the alignment means 333 to one of the chuck platforms 30 shown in FIG. 1, and the second conveying means 336 has the function of being held One of the functions of the chuck platform 30 that has completed the grinding of the wafer W is transferred to the cleaning means 40.

On the rear side (+Y direction side) of the first conveying means 335 on the base 3A, a turntable 34 is arranged. On the top of the turntable 34, for example, three chuck platforms 30 are arranged at equal intervals in the circumferential direction. . The turntable 34 rotates around the axis in the Z-axis direction, whereby one of the chuck platforms 30 is positioned adjacent to the first conveying means 335 or the second conveying means 336.

The chuck platform 30 having a circular outer shape is provided with a suction part 300 which is composed of a porous member or the like and which suctions the wafer W, and a frame body 301 which supports the suction part 300. The suction part 300 is connected to a suction source not shown. The suction force generated by the suction source will be transmitted to the exposed surface of the suction part 300, that is, the suction surface 300a, whereby the chuck platform 30 is on the suction surface 300a. The wafer W is attracted and held. The chuck platform 30 can rotate on the turntable 34.

On the rear side of the base 3A, a column frame 3B and a column frame 3C are arranged side by side, and on the side surface of the column frame 3B on the -Y direction side, a rough grinding means 31 is arranged to grind and feed in the Z-axis direction The first grinding feeding means 35 is provided with a second grinding feeding means 36 for grinding and feeding the finishing grinding means 32 in the Z-axis direction on the side surface of the column frame 3C in the -Y direction.

The first grinding feeding means 35 consists of a ball screw 350 with a vertical axis, a pair of guide rails 351 arranged in parallel with the ball screw 350, a motor 352 that rotates the ball screw 350, and an internal The nut is screwed with the ball screw 350 and the side part is slidably connected to the guide rail 351 by the lifting part 353. In addition, as the motor 352 rotates the ball screw 350, the lifting portion 353 is guided by the guide rail 351 to move up and down, and accordingly, the rough grinding means 31 supported by the lifting portion 353 also moves up and down.

The second grinding and feeding means 36 consists of a ball screw 360 with a vertical axis, a pair of guide rails 361 arranged in parallel with the ball screw 360, a motor 362 that rotates the ball screw 360, and an internal The nut and the ball screw 360 are screwed together and the side part is slidably connected to the guide rail 361 by the lifting part 363. In addition, as the motor 362 rotates the ball screw 360, the lifting portion 363 is guided by the guide rail 361 to move up and down. As a result, the fine grinding means 32 supported by the lifting portion 363 also moves up and down.

The rough grinding means 31 includes a rotating shaft 310 whose axis direction is the Z-axis direction, a spindle housing 311 that rotatably supports the rotating shaft 310, a motor 312 that drives the rotating shaft 310 to rotate, and is detachably connected To the grinding wheel 313 at the lower end of the rotating shaft 310.　　 On the bottom surface of the grinding wheel 313, a plurality of rough grinding stones 313a having a substantially rectangular parallelepiped shape are arranged in a ring shape. The rough grinding stone 313a, for example, diamond stone or the like is fixed and formed with a suitable binder. The rough grinding stone 313a is a stone used for rough grinding, and it is a stone with relatively large stone particles contained in the stone.

For example, in the interior of the rotating shaft 310, a flow path (not shown) that communicates with the grinding water supply source and becomes a passage for the grinding water is formed through the shaft direction of the rotating shaft 310, and the flow path is formed in the grinding wheel 313. The bottom surface is open so that grinding water can be sprayed toward the rough grinding stone 313a.

The fine grinding means 32 is a grinding wheel 313 rotatably assembled with a fine grinding wheel 323a, and the rough grinding means 31 grinds the wafer W thinned to the final thickness. The surface is further ground, and the flatness of the ground surface of the wafer W can be improved. The grinding stone 323a contained in the fine grinding stone 323a has a particle size smaller than that of the rough grinding stone 313a. The structure of the fine grinding means 32 other than the finish grinding stone 323a is the same as that of the rough grinding means 31.

A pair of height gauges 38A and a pair of height gauges 38B for measuring the thickness of the wafer W are respectively arranged at positions adjacent to the rough grinding means 31 and the fine grinding means 32 lowered to the processing position. The pair of height gauges 38A and the pair of height gauges 38B have the same structure, so only the pair of height gauges 38A will be described. The pair of height gauges 38A includes a first height gauge 381 for measuring the height position of the suction surface 300a of the chuck table 30, and a second height gauge 382 for measuring the height position of the back surface Wb of the wafer W. The first height gauge 381 detects the height position of the upper surface of the frame body 301 as the reference surface, and the second height gauge 382 detects the height position of the ground surface of the wafer W, and calculates the difference between the two detected values. The thickness of the wafer W is measured at any time during the cutting.

Hereinafter, a case where the wafer W is ground using the grinding device 3 shown in FIG. 1 will be described. The turntable 34 rotates counterclockwise from the +Z axis direction, and the chuck table 30 moves to the vicinity of the first conveying means 335. The mechanical arm 330 pulls a wafer W from the first cassette 331 and moves the wafer W to the alignment means 333. After the wafer W is positioned to a predetermined position by the positioning means 333, the first transport means 335 transports the wafer W on the positioning means 333 to the suction surface 300a of the chuck platform 30. However, the attraction force generated by an unillustrated attraction source is transmitted to the attraction surface 300a, whereby the chuck platform 30 attracts and maintains the wafer W in the state where the back surface Wb faces the upper side.

The turntable 34 rotates counterclockwise as viewed from the +Z axis direction, whereby the chuck table 30 holding the wafer W moves below the rough grinding means 31 to align the grinding wheel 313 with the wafer W. The alignment is performed, for example, in such a way that the rotation center of the grinding wheel 313 is shifted in the +Y direction by a predetermined distance relative to the rotation center of the wafer W, so that the rotation orbit of the rough grinding wheel 313a passes through the crystal The center of rotation of the circle W.

As the rotating shaft 310 shown in FIG. 1 is rotationally driven, the grinding wheel 313 rotates. In addition, the rough grinding means 31 is fed in the -Z direction by the first grinding feeding means 35, and the rough grinding wheel 313a of the rotating grinding wheel 313 abuts against the back surface Wb of the wafer W, thereby performing rough grinding. Cutting. In addition, as the chuck table 30 rotates, the wafer W held on the suction surface 300a also rotates, so the entire back surface Wb of the wafer W is ground. In addition, the grinding water system is supplied to the contact part of the rough grinding wheel 313a and the wafer W, and the contact part is cooled and cleaned.

The wafer W which is ground to the final thickness by rough grinding is then ground to the final thickness. After the rough grinding means 31 is separated from the wafer W, the turntable 34 rotates in the counterclockwise direction as viewed from the +Z direction, whereby the chuck table 30 moves below the finish grinding means 32. As shown in FIG. 2, after the grinding wheel 313 provided in the fine grinding means 32 is aligned with the wafer W, the fine grinding means 32 is fed in the -Z direction, and the rotating fine grinding stone 323a abuts To the back surface Wb of the wafer W, as the chuck table 30 rotates, the wafer W held on the suction surface 300a rotates, and the entire surface of the back surface Wb of the wafer W is polished. In addition, the grinding water system is supplied to the contact part of the finish grinding stone 323a and the wafer W, and the contact part is cooled and cleaned.

The wafer W, which has been ground to the final thickness by finish grinding to increase the flatness of the back surface Wb, is cleaned by the cleaning means 40 shown in FIG. 1. After the finish grinding means 32 is separated from the wafer W, the turntable 34 rotates counterclockwise from the +Z direction, whereby the wafer W moves to the vicinity of the second conveying means 336. Then, the second transport means 336 transports the wafer W on the chuck table 30 to the cleaning means 40.

The cleaning means 40 shown in FIGS. 1 and 3 is, for example, a single wafer type (single wafer type) spinner cleaning device, which is provided with a holding table 400 for sucking and holding the wafer W, and formed on the base 3A. The container portion 401 surrounded by the holding table 400 from the side, the rotating means 402 arranged in the container portion 401 to rotate the holding table 400, and the method for supplying cleaning liquid to the wafer W held on the holding table 400 Nozzle 403, and shield 404 to prevent the washing liquid from scattering.

The holding table 400 has a circular outer shape, for example, and has a horizontal holding surface 400a that is composed of a porous member or the like and sucks and holds the wafer W. The holding surface 400a is connected to a not-shown suction source, and the attractive force generated by the suction of the suction source is transmitted to the holding surface 400a.

The outer shape of the container part 401 is formed in, for example, a polygonal shape, and a drain port (not shown) is formed in the bottom of the container part 401. In the region on the -X direction side of the inside of the container portion 401, a platform portion 401a on which a swirling means for causing the nozzle 403 to swirl or the like is provided is formed.

As shown in FIG. 3, the rotating means 402 has at least a spindle 402a whose upper end is fixed to the bottom surface side of the holding table 400 and is rotatable about a vertical axis, and a lower end of the spindle 402a which is constituted by a motor or the like. Rotation drive source 402b on the side. The rotating drive source 402b rotates the spindle 402a, and thereby the holding table 400 fixed to the spindle 402a also rotates.

The nozzle 403 that communicates with a cleaning liquid supply source (not shown) to supply the cleaning liquid to the wafer W has an ejection port 403a that opens toward the -Z direction side and ejects the cleaning liquid. The nozzle 403 is supported by the arm 405 that can rotate around the axis in the Z-axis direction, and the injection port 403a can be moved from above the holding table 400 to the retracted position.

The shield 404 shown in FIGS. 1 and 3 includes a side shield 404b that covers the upper shield 404a of the holding table 400 from above, and a side shield 404b that surrounds the holding table 400 from the side, and is integrally formed with the upper shield 404a The bracket guard 404c. The side shield 404b is lowered in FIG. 1 and is located in the container portion 401, and in FIG. 3, it is in a state of rising from the container portion 401.

The side shield 404b, which functions as a switchable gate, is located inside the container portion 401 and has a shape that conforms to the side wall of the container portion 401. In addition, the side shield 404b can be moved up and down with respect to the container portion 401 by an air cylinder or the like. The side shield 404b is lowered when the wafer W is loaded and unloaded to the holding table 400 and is accommodated in the container 401 to become an open state, and when the wafer W is cleaned, it rises and becomes a closed state to prevent the cleaning liquid Waiting for flying away.

The plate-shaped bracket shield 404c is fixed to the -X direction side end of the table portion 401a. The "upper shield 404a" has the same planar shape as the container portion 401 when viewed from the +Z direction, and is formed to extend horizontally from the upper end of the bracket shield 404c toward the +X direction side. When the side shield 404b rises and becomes a closed state, the bottom surface of the peripheral portion of the upper shield 404a will be in contact with the upper end surface of the side shield 404b.

In the cleaning of the wafer W after the finish grinding, first, the side shield 404b is lowered as shown in FIG. In the cleaning means 40, the gap between the upper shield 404a and the container part 401 in the Z-axis direction is opened, and the second conveying means 336 that sucks and holds the wafer W can be entered and exited.

By the second transport means 336, the wafer W is transported to the holding surface 400a of the holding table 400, and the wafer W is sucked and held by the holding table 400 in a state where the back surface Wb is on the upper side. In addition, the second conveying means 336 retreats from the inside of the washing means 40 to the outside. Next, as shown in FIG. 3, the side shield 404b rises from the container portion 401, and the upper shield 404a, the side shield 404b, the carrier shield 404c, and the container portion 401 are formed to clean wafers. Confined space of W.

As shown in FIG. 4, the nozzle 403 orbits, and the ejection port 403 a faces the back surface Wb of the wafer W sucked and held by the holding table 400. The cleaning liquid is supplied to the nozzle 403 from a cleaning liquid supply source (not shown), and the cleaning liquid is ejected from the ejection port 403a to the back surface Wb of the wafer W. In addition, as the rotating means 402 rotates the holding table 400, the wafer W also rotates, so the entire backside Wb of the wafer W is cleaned. Then, the cleaning liquid flows down from the back surface Wb of the wafer W into the container portion 401, and is gradually drained to the outside. After the cleaning of the wafer W is completed, the nozzle 403 orbits to retract from above the wafer W.

The grinding device 3, for example, in the cleaning means 40 shown in FIG. 3, further includes a flat transparent plate 50, a holding means 51 for holding the transparent plate 50, and a moving means for moving the holding means 51 closer to or away from the wafer W 52. In this embodiment, the irradiation means 53 irradiates light from the side of the transparent plate 50, and the imaging means 54 photographs the interference fringes generated by the irradiation of light.

For example, the moving means 52 arranged in the center area of the table portion 401a is an air cylinder, and includes a cylinder 520 having a piston (not shown) inside, and a piston rod 521 inserted into the cylinder 520 and having a piston at one end. The other end of the piston rod 521 is fixed to the lower surface of the arm-shaped holding means 51 extending horizontally on the upper side of the holding table 400. Air is supplied to the cylinder 520 (or discharged) and the internal pressure of the cylinder 520 changes, whereby the piston rod 521 moves in the Z-axis direction, and the holding means 51 moves in the Z-axis direction. The holding means 51 may also be capable of turning around the axis of the Z-axis direction.

For example, the transparent plate 50 formed in the shape of a circular plate is fixed to the lower surface of the tip of the holding means 51. The upper surface 50a and the lower surface 50b of the transparent plate 50 are flat surfaces with high flatness, and the lower surface 50b is parallel to the holding surface 400a of the holding table 400. In this embodiment, as the transparent plate 50, an optical flat plate manufactured by Edmund Optics Japan (product name: TS OPTICAL FLAT MIRROR "ZERODUR") is used. For example, the holding means 51 is equipped with a pressure sensitive sensor, etc., which can sense the normal force applied from the wafer W to the transparent plate 50 when the transparent plate 50 falls and contacts the wafer W, and combines the two The contact is notified to the mobile means 52.

The photographing means 54 is, for example, a camera composed of an optical system that captures the reflected light from the subject and a photographing element (CCD) that outputs an electronic signal corresponding to the reflected light. It is provided with an arm that supports the photographing means 54 The photographing means of 550 moves the means 55, which can be moved around and moved up and down on the holding table 400. In addition, the photographing means 54 may not be movable.

The irradiation means 53 for irradiating the imaging area of the imaging means 54 is composed of, for example, a light source such as a sodium lamp capable of emitting monochromatic light of a certain wavelength (for example, about 589 nm), and a converging lens that limits the beam of the sodium lamp, and is fixed to the washing machine. The lower surface of the upper shield 404a of the cleaning means 40 has an optical axis perpendicular to the horizontal plane. The configuration and arrangement of the irradiation means 53 are not limited to the examples in this embodiment. The place where the irradiation means 53 is arranged may be, for example, the vicinity of the imaging means 54, such as the underside of the arm 550. In addition, the irradiation means 53 may be configured to reflect light emitted from a light source such as a sodium lamp with a half mirror and enter the transparent plate 50. In addition, the irradiation means 53 may be configured to be capable of irradiating laser light of a certain wavelength.

When the processing conditions in the grinding process of the wafer W are not appropriate or as shown in FIG. In some abnormal situations, there will be fluctuations caused by inconsistencies in the thickness of the back surface Wb of the wafer W after grinding, that is, the deformation caused by the height difference of the surface, and the back surface Wb of the wafer W A situation where the flatness becomes low. In view of this, in order to detect the undulation of the back surface Wb of the wafer W after grinding, the undulation detection method of the present invention is implemented.

(1) Holding step "First, as shown in FIG. 5, the cleaned wafer W is sucked and held by the holding table 400 in a state where the surface to be ground, that is, the back surface Wb, for example, is on the upper side.

(2) Contact step The transparent plate 50 located above the holding table 400 is lowered in the -Z direction by the moving means 52, and the lower surface 50b of the transparent plate 50 contacts the back surface Wb of the wafer W. In addition, when the back surface Wb of the wafer W has a large undulation, the lower surface 50b of the transparent plate 50 and the back surface Wb of the wafer W may be in a state of contacting with several points or one point instead of a surface. In addition, the pressure-sensitive sensor of the holding means 51 senses the contact between the transparent plate 50 and the wafer W and notifies the moving means 52 of the information, whereby the lowering of the transparent plate 50 stops.

(3) Irradiation step 　　 Next, the irradiating means 53 irradiates monochromatic light from the transparent plate 50 side, and the irradiated light enters the transparent plate 50 perpendicularly. In addition, it is preferable to form a closed space by the upper shield 404a, the side shield 404b, the bracket shield 404c, and the container portion 401, so as to prevent excess light other than the light irradiated by the irradiation means 53 from outside Incident. When the thickness of the back surface Wb of the wafer W after the grinding is uneven due to fluctuations, there will be a small amount of undulation between the lower surface 50b of the transparent plate 50 contacting the wafer W and the back surface Wb of the wafer W. gap. Therefore, due to the air layer existing in this minute gap, the light reflected on the lower surface 50b of the transparent plate 50 and the light reflected on the back surface Wb of the wafer W interfere to form interference patterns (Newton's rings).

The focusing point, position, and magnification rate of the interference fringes generated by the irradiation of monochromatic light are determined, and the imaging means 54 captures the interference fringes with a camera (CCD), for example, to form a photographed image including the entire transparent plate 50. In addition, the photographed image formed by the photographing means 54 may also be an image that includes a part of the upper surface 50 a of the transparent plate 50. For example, a detection means 8 is connected to the imaging means 54. The detection means 8 observes and measures the interference pattern in the captured image formed by the imaging means 54 and detects the undulations of the back surface Wb of the wafer W. The imaging means 54 Send information about the formed captured image to the detection means 8.

The detection means 8 displays the captured image of the interference pattern R on the output screen B with a predetermined resolution shown in FIG. 6, and detects the backside Wb of the wafer W from the interference pattern R displayed on the output screen B. ups and downs. For example, the smaller the number of interference fringes R and the closer the shape of the interference fringes R is to a circle, the flatness of the back surface Wb of the wafer W is high and there are few fluctuations. For example, where the interference fringe R is concentrically spaced at unequal intervals, it is possible to detect that the back surface Wb of the wafer W has gentle spherical undulations. In addition, where the interference fringe R has, for example, two sets of hyperbolic shapes, saddle-shaped undulations on the back surface Wb of the wafer W can be detected.

For example, the inspection means 8 can also be designed to perform the following equation 1 with the detection of fluctuations to calculate the surface accuracy of the back surface Wb of the wafer W, that is, the height difference between the highest position and the lowest position of the back surface Wb of the wafer W . (Wavelength of irradiated light/2)×(curvature of interference fringe R/interval between interference fringes R)=surface accuracy...(Equation 1) 　　 In addition, for example, it may be designed to be arranged on the bottom side of the holding table 400 A tilt adjustment mechanism that adjusts the tilt of the holding surface 400a of the holding table 400, whereby the tilt adjusting mechanism tilts the back surface Wb of the wafer W attracted and held by the holding table 400 with respect to the horizontal plane, and is caused by the irradiation means 53 The light irradiation and the formation of the photographed image by the photographing means 54, the detection means 8 monitors the moving direction of the interference pattern R displayed on the output screen B, thereby determining the undulating unevenness of the back surface Wb of the wafer W. In addition, it may be designed to be able to calculate the non-uniformity of the thickness of the wafer W. In addition, as a configuration in which the holding means 51 can adjust the inclination of the transparent plate 50, it can also be designed to be able to adjust the inclination of the lower surface 50b of the transparent plate 50 to monitor the movement direction of the interference fringe R.

The method for detecting the undulation of a wafer of the present invention includes a holding step of holding the wafer W on the holding table 400, a contact step of bringing the flat transparent plate 50 into contact with the wafer W held on the holding table 400, and for example In the irradiation step of irradiating light on the side of the transparent plate 50, the fluctuation of the wafer W can be detected by the interference fringes R generated in the irradiation step. In addition, the method for detecting the undulation of the wafer of the present invention can be implemented in the grinding device 3 without the need to make the device configuration of the grinding device 3 complicated. Therefore, it is not necessary to use the grinding device to detect the undulation of the wafer W. 3 The wafer W is taken out and transported to another measurement device, so it is possible to prevent an increase in the number of processes required for processing.

In addition, the grinding device 3 of the present invention includes a flat transparent plate 50, a holding means 51 for holding the transparent plate 50, and a moving means 52 for moving the holding means 51 closer to or away from the wafer W, and from the side of the transparent plate 50, for example. The irradiating means 53 for irradiating light and the imaging means 54 for photographing the interference fringes R generated by the irradiation of light can detect the undulation of the wafer W in the grinding device 3. Therefore, it is not necessary to take out the wafer W from the grinding device 3 and transport it to another measuring device in order to detect the undulation of the wafer W, and it is possible to prevent an increase in the number of processes required for processing. In addition, it is possible to detect the fluctuations of the wafer W in the grinding device 3, so that it is possible to quickly detect the factors that cause fluctuations that exceed the allowable value on the ground surface of the wafer W, that is, the back surface Wb, that is, grinding. Each component of the device 3 (for example, the rotating shaft 310 of the finishing grinding means 32, etc.), an abnormality in the finishing grinding stone 323a, and an abnormality in the processing conditions.

In addition, the grinding device 3 of the present invention and the wafer undulation detection method of the present invention are not limited to the above-mentioned embodiment. In addition, the configuration of the grinding device 3 shown in the drawings is not limited to this. It can be appropriately changed within the range where the effects of the present invention can be exhibited. For example, the arrangement of the transparent plate 50, the holding means 51, the moving means 52, the irradiation means 53, and the photographing means 54 is not limited to the washing means 40, for example, it may be designed as a second conveying means on the base 3A The transparent plate 50, the holding means 51, the moving means 52, the irradiating means 53, and the photographing means 54 are arranged adjacent to the 336, so that the undulation detection method of the present invention can be implemented on the wafer W held on the chuck platform 30. "In addition, the wave detection method of the present invention can also be designed to be implemented after the rough grinding of the wafer W by the rough grinding means 31 is completed.

W‧‧‧Wa‧‧‧The surface of the wafer Wb‧‧‧The back of the wafer 300‧‧‧Adsorption part 300a‧‧‧Adsorption surface 301‧‧‧Frame body 31‧‧‧Rough grinding means 310‧‧‧Rotating shaft 311‧‧‧Mandrel shell 312‧‧‧Motor 313‧‧‧Grinding Wheel 313a‧‧‧Rough grinding of the stone 32‧‧‧Fine grinding means 323a‧‧‧Fine grinding of the stone 330‧‧Mechanical arm 330a‧‧‧arm 330b‧‧holding part 331‧‧‧first cartridge 332‧‧‧Second cartridge 333‧‧‧Alignment means 335‧‧‧First conveying means 336‧‧‧Second conveying means 34‧‧‧Turntable 35‧‧‧First grinding and feeding means 350‧‧‧Ball Screw 351‧‧‧Guide 352‧‧Motor 353‧‧‧Elevating part 36‧‧‧Second grinding and feeding means 360‧‧‧Ball screw 361‧‧‧Guide 362‧‧‧Motor 363‧‧‧Elevating part 38A , 38B‧‧‧A pair of height gauge 381‧‧‧The first height gauge 382‧‧‧The second height gauge 40‧‧‧Washing means 400‧‧‧Holding table 400a‧‧‧Holding surface 401‧‧‧Container Part 401a‧‧‧Ten part 402‧‧‧Rotation means 402a‧‧‧Mandrel 402b‧‧‧Rotation drive source 403‧‧‧Nozzle 403a‧‧‧Injection port 404‧‧‧Guard 404a‧‧‧Upper guard 404b‧‧‧Side guard 404c‧‧‧Bracket guard 50‧‧‧Transparent plate 51‧‧‧Holding means 52‧‧‧Moving means 520‧‧Cylinder 521‧‧‧Piston rod 53‧‧‧Lighting Means 54 ‧ ‧ Shooting means 55 ‧ ‧ Shooting means Moving means 8 ‧ ‧ Detection means B ‧ ‧ Output screen R ‧ ‧ Interference pattern

[Figure 1] A schematic perspective view of an example of a polishing device.　　[Figure 2] A schematic cross-sectional view of the state of the fine grinding of the back surface of the wafer by fine grinding means.　　[Figure 3] A schematic perspective view of an example of the inside of the cleaning means.　　[Figure 4] A schematic cross-sectional view of the state where the backside of the wafer is being cleaned by a cleaning means.　　[Fig. 5] A schematic cross-sectional view of a state where the interference pattern generated by irradiating light from the side of the transparent plate is photographed in a state where the transparent plate is in contact with the back surface of the wafer.　　[Figure 6] A schematic explanatory diagram showing an example of a captured image with interference fringes displayed on the output screen.

8‧‧‧Detection method

40‧‧‧Washing method

50‧‧‧Transparent board

50a‧‧‧Top of transparent plate 50

50b‧‧‧Under the transparent plate 50

51‧‧‧Keep the means

52‧‧‧Means of movement

53‧‧‧Lighting

54‧‧‧Photography

55‧‧‧Movement means of shooting

400‧‧‧Holding Taiwan

400a‧‧‧Keep the surface

401‧‧‧Container Department

401a‧‧‧Taiwan Department

402‧‧‧Rotating means

402a‧‧‧Mandrel

402b‧‧‧Rotation drive source

404‧‧‧Shield

404a‧‧‧Upper guard

404b‧‧‧Side guard

404c‧‧‧Bracket guard

520‧‧‧Cylinder

521‧‧‧Piston rod

550‧‧‧arm

W‧‧‧wafer

Wa‧‧‧The surface of the wafer

Wb‧‧‧The back side of the wafer

Claims (3)

A method for detecting fluctuations of a wafer, comprising: a holding step of holding the wafer in a holding table; and a cleaning step of cleaning the wafer held in the holding table; and after the cleaning step is performed, The step of contacting the flat transparent plate with the wafer held on the holding table; and the step of irradiating light from the side of the transparent plate; and detecting the fluctuation of the wafer due to the interference pattern generated in the step of irradiating. A grinding device is provided with a grinding means, a chuck platform for holding a wafer, and a washing means for washing the wafer, characterized in that the washing means is further equipped with: flat and transparent Plate; and holding means for holding the transparent plate; and moving means for making the holding means close to or away from the wafer; and irradiating means for irradiating light from the side of the transparent plate; and photographing interference patterns generated by the irradiation of the light The photographing means; in the washing means, the photographing means is used to photograph the interference pattern generated by irradiating the light from the side of the transparent plate by the irradiating means on the wafer that has been washed. The grinding device according to claim 2, wherein the cleaning means is provided with a shield that prevents the scattering of the cleaning liquid, and when the light is irradiated from the transparent plate side by the irradiating means, avoiding the use of The excess light other than the light irradiated by the irradiating means enters from the outside of the washing means The washing means inside.

Images